Purpose:
Logarithmic transformation of retinal thickness (logOCT) has recently been shown to provide analytic advantages compared to central subfield thickness (CST) in evaluating clinically relevant changes in retinal thickness. The purpose of this study was to evaluate the utility of logarithmic transformation of spectral-domain OCT (logSD-OCT) in evaluating clinically relevant changes in macular edema secondary to uveitis.
Methods:
Patients with noninfectious, endogenous uveitis who underwent baseline SD-OCT imaging from a tertiary referral academic setting were identified. The anatomic diagnoses, visual acuities (VA), presence/absence of macular edema, and central subfield thicknesses from the Zeiss Cirrus HD-OCT manufacturer’s software were recorded. Logarithmic transformation of SD-OCT was performed. Frequency histograms were plotted for CST and log(SD-OCT). Skewness and kurtosis of both data sets were determined. Correlation of the logarithm of the minimum angle of resolution (logMAR) VA with CST and log(SD-OCT) were performed.
Results:
Twenty-eight SD-OCT images from 14 patients with uveitis-associated macular edema were analyzed. Anatomic diagnoses included anterior/intermediate uveitis (7%), intermediate uveitis (7%), posterior uveitis (36%), and panuveitis (50%). Logarithmic transformation of SD-OCT data provided a more normal distribution than CST derived from SD-OCT images in uveitic macular edema (Figure 1). Skewness and kurtosis of CST data were 2.175 and 6.907, respectively. Skewness and kurtosis of log(SD-OCT) data were 0.7931 and 1.964. Poor correlation was observed between both logMAR VA with CST (Pearson r=0.087, p> 0.05) and logMAR VA with log(SD-OCT), (Pearson r =0.029, p>0.05).
Conclusions:
Log(SD-OCT) and CST demonstrated poor correlation with logMAR VA in uveitic macular edema, consistent with prior literature in other retinal conditions. However, the more normal distribution of logarithmic transformation of SD-OCT of retinal thicknesses in this patient population may be valuable for the assessment of clinically meaningful SD-OCT changes in uveitis research.
Keywords: imaging/image analysis: clinical • clinical (human) or epidemiologic studies: biostatistics/epidemiology methodology • edema